Configuring Joining at the Mapping Level

TopLink supports configuring an inner join at the mapping level for one-to-one mappings only. When a class that owns the mapping is read, the TopLink runtime will always get the class and the target of the one-to-one mapping with one database hit.

Use this feature only if the target object is always required with the source object, or when indirection is not used.

You can also configure join reading (see "Join Reading and Object-Level Read Queries") at the query level.

For more information about joins, see "Expressions for Joining and Complex Relationships".

Using TopLink Workbench

To use joining in a relationship mapping, use this procedure:

1. Select the mapped attribute in the Navigator. Its properties appear in the Editor.

2. Click the General tab. The General tab appears.

   Figure 40-1 General tab, Use Joining option

   
   Description of "Figure 40-1 General tab, Use Joining option"
   
   

To use joining with this relationship, select the Use Joining option.